Arctic sea ice on August 26, the day the sea ice dipped to its smallest extent ever recorded in more than three decades of satellite measurements Scientific Visualization Studio, NASA Goddard Space Flight Center

The Arctic sea ice extent yesterday fell below its previous record low and is currently losing frozen sea at the rate of about 29,000 square miles (roughly 75,000 square kilometers) a day. That's equivalent to an area the size of South Carolina every 24 hours.

Here's what happened:

On August 26 sea ice extent fell to 1.58 million square miles (4.10 million square kilometers).

That's 27,000 square miles (70,000 square kilometers) below the previous record set on September 18, 2007.

The 2007 record low ice extent was 1.61 million square miles (4.17 million square kilometers).

Note that this year's record low was set more than three weeks earlier than the 2007 record. And summer isn't over yet. There's more melting to come.

Arctic sea ice extent as of August 26, along with daily ice extent data for 2007, the previous record low year, and 1980, the record high year: National Snow and Ice Data Center courtesy Rutgers University Snow Lab.

What's alarming is that the 2007 record was set during a year of near-perfect conditions for melting. This year didn't have anything like perfect conditions. But even that couldn't stop the freight train running down those Arctic tracks.

According to National Snow and Ice Data Center (NSIDC) Director Mark Serreze: "The ice is so thin and weak now, it doesn't matter how the winds blow."

The six lowest ice extents in the satellite record have occurred in the last six years, from 2007 to 2012.

This trend is an indication that the Arctic sea ice cover is fundamentally changing, said NSIDC scientist Walt Meier. "The Arctic used to be dominated by multiyear ice, or ice that stayed around for several years. Now it's becoming more of a seasonal ice cover and large areas are now prone to melting out in summer."

Scattered ice floes seen from the bridge of US Coast Guard icebreaker Healy on August 20, northwest of Barrow, Alaska: US Coast GuardThe photo above shows the view from the US Coast Guard icebreaker Healy, a science research ship that runs north looking for ice. They've been having problems finding it the last few summers.

BTW, I'm headed out aboard Healy for their last Arctic run of the year in October. I'll let you know what I see up there. And what that might mean for the people and wildlife of the Arctic. Not to mention all the rest of us who've kind of gotten used to the effects of its frozenness on the planet.

The National Toxicology Program, part of the National Institutes of Health, publishes the biannual Report on Carcinogens, which is one of the primary sources of up-to-date public information about chemicals that are known or suspected causes of cancer. The report has been published since 1980, in response to a directive from Congress. But if Rep. Denny Rehberg (R-Mont.) gets his way, soon we might lose this detailed information about the chemicals putting us at risk.

Rehberg's proposed Labor, Health and Human Services funding bill for 2013 would eliminate the budget for the Report on Carcinogens (RoC) until the agency follows through with an additional follow up to its 2011 report. (Rehberg's proposal contains a number of highly political cuts, including all funding for President Barack Obama's Affordable Care Act, Planned Parenthood, and family planning.)

A few months later, the industry's Republican allies in Congress appended a conference report to the 2012 Consolidated Appropriations Act directing the Health and Human Services to contract with the National Academy of Sciences (NAS) to conduct a review of the RoC's determinations on those two chemicals. As NIH has already affirmed, the Report on Carcinogens is both peer-reviewed itself and drawn from independent, previously peer-reviewed literature.

HHS is in the process of contracting with NAS to complete that review, but apparently it's not happening fast enough for Rehberg. He and Rep. Hal Rogers (R-Ky.), chairman of the appropriations committee, wrote a letter to Sec. Kathleen Sebelius earlier this month asking her to expedite the process. A spokesperson for HHS told Mother Jones the agency is "reviewing the letter and will respond in timely manner."

Meanwhile the budget bill Rehberg and Rogers drafted for next year would bar the National Toxicology Program from doing any work on the next Report on Carcinogens, due out next year, until 30 days after that NAS report is complete.

If included in the final funding bill, this could mean no new RoC report for years to come. NAS reports tend to be long and detailed; a spokesman for NAS told Mother Jones that reports can take anywhere from three months to five years. If the National Toxicological Program has to wait until the NAS evaluation is complete to do anymore work, it would be hard to say when the next RoC would be ready.

Environmental health advocates are watching the Rehberg bill with concern. "Make no mistake. This isn't an effort to get a more accurate, scientifically-based answer on whether these chemicals are carcinogens," said Jason Rano, director of government affairs with the Environmental Working Group. "This is an effort to get a favorable outcome for industry's bottom line." The American Sustainable Business Council is also asking Congress to protect the report.

Cancer has become a big issue in Rehberg's Senate race, with the congressman trading jabs with incumbent Democrat Jon Tester about support for cancer screenings. Rehberg's campaign touts him as a "strong supporter of funding for cancer research, control and prevention." But when it comes to the things that might cause cancer, he seems to be less enthusiastic.

Last year, the Mississippi River flooded. Major storms combined with melting snow brought the waterway more than 56 feet above river stage in May. The Army Corps of Engineers lifted the floodgates of the Morganza Spillway, deliberately inundating some 3,000 square miles of rural Louisiana to spare worse damage in New Orleans and Baton Rouge. In August of last year, NASA's Landsat 5 satellite took a picture of the swollen river. Here's what it saw:

This year it's an entirely different story. At the end of last month, more than 60 percent of the lower 48 states were in drought, and the might Mississippi was running low. An 11-mile stretch of river has been closed on and off since August 11, and earlier this week nearly 100 boats lined up near Greenville, Mississippi, waiting to pass. Water levels near Memphis are ranging from 2.4 to 8.3 feet below river stage, compared with 11.7 feet above at this time last year. To make matters worse, the floods of last year deposited huge amounts of sediment on the river bed, reconfiguring the existing channels.

Again NASA was there to capture the view from space, this time with Landsat 7. Here's that image:

Of course the indirect costs—the lost revenue to the ports along the way, to the businesses whose shipments are delayed, not to mention the toll on the ecosystems that depend on water from the river—those costs are much, much greater.

Research labs are home to mice of all sizes and shapes and genes. There's your common and ordinary dark-coated Black-6, one of the most intensely scrutinized animals on the planet. And then there are...well, see for yourself:

Nude mouse

Baldness is only the most obvious thing strange about this mouse. The same mutation that make it hairless also severely weakens its immune system, so that it no longer rejects grafts of foreign tissue, even from a different species. And if you're a cancer researcher, the foreign tissue of interest is human tumors. Implanting human cancer cells under the skin of immunodeficient mice and testing candidate drugs is a standard technique in research. If the tumor shrinks, then ring-ding-ding, you've got a potential cancer drug. In the past couple of decades, researchers have leveled up to hairless mice with more fully defunct immune systems, having not one but three nonfunctional immune genes.

"Earmouse"

At least this cartilage on my back is better than a tumor?WikipediaLet's begin with what this is not. This is not a human ear growing on a mouse. This is a piece of cow cartilage that just so happens—okay fine, it was on purpose—to be in the shape of a human ear.

Those of lucky enough to have two intact ears have probably never thought about how oddly shaped ear cartilage is. But for doctors, that means that trying to growing cartilage in the right shape for ear reconstruction is difficult. Dr. Charles Vacanti in 1997 created a biodegradable scaffold seeded with cow cartilage cells. Implanted in a nude mouse, the animal's blood vessels nourished the cartilage cells until they grew to replace the simultaneously dissolving scaffold. This piece of cartilage was never implanted in a human—cow cartilage, after all, would be rejected by a normal immune system—but Dr. Vacanti used a similar technique to grow the chest plate of a 16-year-old boy born without cartilage on his left side.

Not (entirely) hairless mouse

Nature CommunicationsSometimes scientists use bald mice for tissue grafts, and sometimes scientists use them just because they're bald. This little tuft of hair here could someday be the salve of balding men. Earlier this year, Japanese researchers reported successfully growing hair by implanting human or mouse stem cells into the skin of nude mice. The hair follicles even connected to nerves and muscle, so these albeit wispy-looking hairs could stand on their ends, just like when you get goose bumps.

How shall we put it? This is a mouse with the asshole of a human. Missing an ear or some hair is inconvenient, but missing a functional anal sphincter, as can happen due to injuries during childbirth, makes life actually difficult. These lab-built sphincters are made of human muscle cells and mouse nerves. Implanting the petri dish-grown sphincter under the skin of mice proved it could link up to blood vessels and nerves of the animal. Now, it didn't actually replace the mouse's own anal sphincter, but that experiment is in progress.

In the summer of 1949, some very normal-looking mice were born into The Jackson Laboratory in Maine. As time passed however—21 days in photo A, 10 months in photo B—these mice showed a voracious appetite, eating and eating until they ballooned into small fur pillows with tails. With fat cells both abnormally large and numerous, the mice weighed as much as three of their lean counterparts.

These were the first ob/ob mice, so named because they have two defunct copies of the ob gene. This strain has become widely used in obesity and diabetes research, and The Jackson Laboratory is now one of the largest mouse breeding facilities in the US, providing research labs with milions of mice like this.

Real life Frankenstein—conjoining an obese mouse with a normal mouse

Figuring out how the ob gene actually worked took decades and a Frankenstein-like technique called parabiosis. Think conjoined twins, except the two "twins" aren't related. Parabiosis requires making a shoulder-to-hip incision down the sides of two mice and delicately sewing them together. Once the wound healed, the conjoined mice share one the same blood.

In one the most famous parabiosis experiments, Douglas Coleman conjoined an obese ob/ob mouse with a normal one. Becoming attached to a normal mouse "fixed" some of the health problems in ob/ob, making it eat less, have lower blood sugar, and lose weight. This and other parabiosis experiments with diabetic mutants led Coleman to conclude that ob/ob mice lacked in their blood a "satiety factor," or some hormone that let them know when they were hungry. That's why sharing blood with a normal mouse helped.

In 1994, 45 years after ob/ob was first discovered, scientists finally pinpointed the exact gene that madethemice obese. Indeed, the gene made a hormone called leptin that regulates appetite and metabolism. As in mice, problems with leptin can cause obesity in humans.

A tumor for every follicle

While the leptin gene find took years and years to find in the 90s, geneticists today have sophisticated techniques that easily target single genes. Knockout mice lacking a specific gene and transgenic mice engineered to have additional genes are workhorses of the modern lab.

This transgenic K5ras mouse (pdf) Current Biologyis one example. Aside from studying implanted tumors in nude mice, cancer researchers also work with genetic models, and overexpression of the ras gene makes mice especially prone to cancer. The prefix K5 refers to a genetic tag that means ras only gets overexpressed in the skin of this mouse. And overexpressed it is. In this barely recognizable muzzle of mouse, there's a tumor in every follicle. About 20 percent of all tumors have mutations that make ras overactive, so it's a key cancer gene.

Aerial spraying to combat the West Nile virus will continue Friday night across north Texas despite the concerns of residents worried about potential health risks posed by the insecticide.

Dallas is the center of the worst West Nile outbreak in the US this year, which prompted local officials to declare a state of emergency on Wednesday and dispatch two airplanes to spray the city and surrounding areas last night.

The planes left Dallas' Executive Airport as planned at 10pm last night but were only able to spray about 52,000 acres, just over half their target, because of rain.

Wildfire smoke: Dan Pearce via FlickrThe National Interagency Fire Center reports that 2012 just broke the record for most acreage burned by wildfires as of this date (see chart below). The previous record was set in 2006, another mega-drought year.

That's nearly 7 million acres—or 10,893 square miles—that have burned so far this record hot and dry year. Currently 39 large fires and fire complexes are actively burning 1,401,968 acres.

Night view of western wildfires, August 17 NASA image by Jesse Allen, using Suomi NPP VIIRS dataIn Northern California, where I live, fire bloomed with August's dry lightning strikes. Since even the biggest lightning-sparked fire starts out as something small, maybe just a single smoldering tree, sometimes someone finds that tree in time.

Then came the report of a lightning fire burning in rugged terrain southeast of Eagle Lake. The fire had been spotted from the summit, but at night no aircraft could be used for reconnaissance and there were no direct roads into the forested area. So in the dark, with a flashlight and a radio, this one guy went off hiking into the woods to find a fire. We all sat listening to the radio and wondered out loud—what do they call him? Is there actually a name for this job? Is he a 'smoke-hiker' or 'fire-walker'?

All we knew for sure is that in the dark of the night this guy had set off on his own through some of the most intimidating wilderness in the county searching for a fire, walking through woods that aren't easy-going in the daytime, in conditions where smoke filled the air, and made visibility almost zero... [A]fter two hours of hiking in the dark smoky night through road-less forest, our hero found it… a single pine tree burning in heavy undergrowth which in itself was on fire in every direction for 50 to 100 yards... Our 'smoke-walker' then began the almost 1-hour trek back out from the fire to meet the crew, turned around and guided them back to the fire as quickly as possible.

Plus the global costs. As Jeff Masters writes, a recent study suggests that while 8 percent of Earth should see decreases in fire activity over the next 30 years of global warming, 38 percent should see increases.

And then there are the personal costs. In my case, newly diagnosed with asthma, that means learning to live with canaries—I mean, bronchi—in my chest, letting me know with crazy sensitivity just how much particulate is in my little portion of the atmosphere. Suddenly fire and smoke maps like the one above are interactive in a whole new way.

This certificate from USS Nimitz just made it on the short list of what to save from my house in the event of fire. It commemorates my landing aboard the nuclear-powered aircraft carrier at sea off Hawaii last month—part of the Navy's Great Green Fleet Demonstration whereby a carrier strike group and all its aircraft were fueled by alternatives: nuclear and biofuel blends. I'm writing more about my night aboard Nimitz and the US Navy's rad new initiatives regarding energy and climate change for a forthcoming piece in Mother Jones.

This summer I've been on a blueberry tear. I buy a little container from the farmers market or supermarket and open it up as soon as I get home, popping the sweet little orbs into my mouth as I'm putting away my groceries. Only occasionally do I give rinsing them more than a passing thought. After all, I usually splurge for the organic kind. How bad could a little chemical-free dirt really be? Do I really have to wash my innocent-looking blueberries?

According to Sonya Lunder, a senior analyst with the Environmental Working Group, the answer is an unequivocal yes, for several reasons. One is what the produce industry refers to as "pesticide drift": The wind can—and frequently does—blow chemicals from nearby conventional fields onto organic crops.* Pesticide contamination can also happen in the warehouse, since many produce companies use the same facilities to process organic and conventional products. In that case, companies are supposed to use the label "organically grown" instead of "organic," which can mislead consumers. "The labels are really confusing," Lunder says. "When people say they're transitional organic, there might be traces left in the soil. If you see no-spray, they still might be using synthetic fertilizer, for example."

But the main reason to wash organic produce is to get rid of germs. "Bacterial contamination is huge," Lunder says. You might remember, for example, that one of the culprits in the giant E. coli spinach outbreak of 2006 was bagged organic spinach.

I immediately set about emailing shark experts. The Monterey Bay Aquarium declined to comment. The Vancouver Aquarium was more willing to put a toe in the water. "Honestly, I think the jury is still out on this question," emailed Ann Dreolini, a spokeswoman. "According to what I have read so far, there are people who believe the chance of a shark attack is greater while menstruating…and others who think this has absolutely no impact on shark attacks at all."

But Ralph S. Collier, a shark behavior expert who has been documenting shark attacks since 1963 and now heads up the nonprofit research and conservation group Shark Research Committee, told me about a study that his friend and fellow shark expert H. David Baldridge conducted in the late '60s. I couldn't find the study online, but according to Collier, Baldridge introduced several human body fluids—including menstrual blood—to captive wild sharks in open ocean pens to see if any would elicit a feeding frenzy. The only one that did cause such a reaction was peritoneal fluid, the liquid found in our abdominal cavity. (Unfortunately, said Collier, Baldridge's grant money ran out before he could figure out what was so bewitching to sharks about our gut fluid.)

Collier noted that blood from animals native to the marine environment do elicit feeding frenzy reactions in sharks. "But our blood is different from a sea otter's blood or cetacean blood," he said. "Our blood is from a terrestrial environment." He theorizes that the scent of human blood doesn't send the message to sharks that there is an animal in distress nearby, fit for a meal.

Still, he said, Baldridge's study was not comprehensive, and he advises people with abrasions not to go into the ocean. "If it's a young lady for whom it's that time of the month," he added, sounding somewhat uncomfortable, "it's better to be safe than sorry. Better to wait till everything is back to normal to go into the ocean."

Tell that to Marie Levine, founder and executive director of another nonprofit called the Shark Research Institute. "I've been diving for decades and even got my period while underwater with a school of hammerheads—the sharks were not interested and I had to fin like crazy to get close to them," she wrote to me in an email.

And then there's this page over at the Florida Museum of Natural History. Ichthyologist George H. Burgess writes:

Menstrual blood almost certainly can be detected by a shark, and I'm sure urine can be as well. Do we have positive evidence that it is a factor in shark attack? No, and until some menstruating and non-menstruating divers volunteer to take part in a controlled test we'll never prove it. In my opinion it likely is attractive to sharks in certain situations.

Interestingly, according to Burgess, 90 percent of recorded shark attacks have involved men. But that doesn't necessarily mean that sharks are gender-biased:

This reflects a historic pattern of more males engaged in marine aquatic activities, especially those that put humans most at risk, e.g. surfing, diving, long distance swimming, warfare. It in no way can be attributed to sharks "preferring" males over females. In recent years proportionately more females are being attacked because more females are engaging themselves in riskier, formerly males-only activities.

In conclusion, Burgess advises: "Don't worry about it. Lots of women safely dive while menstruating." On the other hand, if you prefer not to participate in freezing and dangerous sports made more dangerous by the presence of sharks, "I'm having my period" seems as good an excuse as any.